Digital Corner

The pH scale is set from 0 to 14 with the low values being very acidic ranging up to very basic. The value in the middle at 7.0 is neutral. Anything below is consider to be acidic. In a lab setting when the soil test value drops below 6.5, we ask for a buffer pH to be completed. A low pH is indicating an acid condition. The buffer pH (BpH) determines the reserve acidity and is used to determine how much limestones is required to neutralize the acidity. This results in the application rate to be applied, it also assumes we will use a limestone with an Ag Index of 75. The Ag Index is required for evaluating the neutralizing value of the limestone, not all limestone is the same. 

The limestone neutralizing value is affected by particle size distribution and the calcium carbonate or neutralizing value (done in a lab by titration). The particle size and neutralizing value are combined into single index value that allows us to compare lime sources in order to choose the most economical limestone and adjust the rate of application. As an example, if the limestone recommendation is for 3000 lbs. per acre based on an Ag Index of 75 and the limestone being considered has an index of 60 then the limestone adjusted rate is now 75/60 x 3000= 3750 lbs. per acre. This adjusted rate will offer the same neutralizing value as limestone with an index of 75 applied at 3000 lbs. Cheaper limestone is usually coarser with lower neutralizing value and lower index requiring a higher rate of application. Be aware that cheap limestone will not likely provide the proper pH adjustment soon enough to increase crop performance and could very well end up being more expensive in the long run. If the Ag Index was 80 then the rate adjustment is 75/80 x 300 = 2812 lbs. per acre.

There are two basic types of limestone, dolomitic which contains both calcium and magnesium and Calcitic limestone containing calcium only with perhaps trace amounts of magnesium depending on the quarry it originated from. Generally speaking, sandy soil is where dolomitic is used as rule as sandy soil tends to be low in both calcium and magnesium when soils are acidic.

The following chart illustrates the influence of soil pH on nutrient availability. Where the horizontal bars which represent each essential nutrient are the widest, versus the pH on the top represents the optimum plant availability of that nutrient in the pH range. 

You notice with micronutrients of Zinc, Manganese, Boron and Copper the availability decreases with the higher soil pH. The Phosphorus availability declines below pH of 5.0 and again at pH of 6.5.

We will explore this more next week.  

Article by Jayden Mallette

Crop Sales Specialist

AGRIS Co-operative

Leamington

The Nitrogen Cycle is a dynamic process encompassing nitrogen in many different forms. Some forms of nitrogen are plant available such as ammonium (NH4+) or nitrate (NO3-), while other forms of nitrogen are not. To understand the importance of nitrogen stabilizers, the nitrogen cycle as a whole, must be looked at first. There are three main processes in the nitrogen cycle that work to increase plant available N; biological fixation, mineralization, and nitrification.

Biological fixation: Atmospheric nitrogen is converted to organic nitrogen via legume plants. These legumes will take in nitrogen gas (N2) and convert them to ammonia (NH3), then organic nitrogen (R-NH2). The final organic nitrogen product that can be used by legumes.

Mineralization: Microbes digest organic nitrogen from crop residues, creating ammonia (NH3), and later ammonium (NH4+). The final product, ammonium, is then able to be taken up by growing plants.

Nitrification: Soil bacteria convert ammonium (NH4+) to nitrite (NO2-), then to nitrate (NO3-). While nitrate is a plant available form of nitrogen, it is extremely prone to leaching, resulting in loss from the soil.

There are three main losses of plant available nitrogen within the nitrogen cycle; leaching, denitrification, and volatilization.

Leaching: Since nitrate ions have a negative charge, they are not attracted to the negatively charged soil sites.  The result is nitrate ions moving freely with the downward flow of water. In excessively wet years and in light textured sandy soils, nitrogen losses through leaching can be extreme.

Denitrification: Soil microbes can convert nitrate (NO3-) into atmospheric nitrogen (N²) that is then able to escape back into the air. This often happens during warm and wet conditions, when oxygen levels in the soil are low. Poorly drained heavily textured clay soils, high in organic matter that stay saturated for more than 48 hours after heavy rainfall events is when N² gas and nitrous oxide emission are produced. 

Volatilization: The loss of nitrogen through ammonia gas. Surface applied unincorporated urea fertilizers such as urea or UAN are hydrolyzed by urease enzymes creating ammonia loss from urea.

Urease Inhibitors

Urease inhibitors job is to decrease nitrogen losses from volatilization. The active ingredient in these inhibitors will bind to the active site of urease enzymes, temporarily preventing them from catalyzing the reaction of urea to ammonia  nitrogen.

Nitrification Inhibitors

Nitrification inhibitors work to slow the conversion of soil ammonium to nitrate. This will slow the loss from nitrogen conversion and allow nitrogen to be available in the soil when the plant needs it. Nitrate nitrogen is the only form of nitrogen that can be lost from the soil from leaching or denitrification. 

Consider adding a urease inhibitor such as Anvol to surface applied urea fertilizers and or a dual inhibitor such as Tribune to UAN that slows volatilization and nitrification loss to your fertilizer applications this crop year.

As we turn the corner in April it is time to fertilize our hay and pasture ground. A current soil sample is the first step in applying a balanced fertilizer program. The soil pH and potassium levels are the top 2 concerns on established forage stands. The other 2 primary nutrients are nitrogen, phosphate and the secondary nutrient sulphur are all of equal importance.

On stands high in alfalfa the micronutrient Boron plays a critical role in rapid growth and yield. This nutrient gets overlooked. It should be part of the annual application of nutrients to avoid deficiencies.

Forages should be managed as well as if not more so than corn and soybeans .The tonnage and nutrient values greatly influence feed cost and animal performance.

Depending on what forage you are growing will determine the nutrient recs. Alfalfa has a large need for potash and sulphur. Grasses have a higher need for nitrogen and sulphur with a little less potash.

Applying fertilizer early will increase tonnage for first cut. Grass will respond to nitrogen and sulphur. With the variability in weather I am a  believer in splitting the application, potentially a second pass after first cut for mixed forages.

Article by Graham McLean

Crop Sales Specialist

AGRIS Co-operative

Glencoe

The price of hay has maintained its high price levels over the last few years. These forage crops rival corn and soybeans for gross revenue per acre, we need to fertilize accordingly.

Another practice that one needs to try is the application of fungicide on high alfalfa stands. Best to do after 1^st cut when the crowns re-establish growth. If one can keep the stands healthier one could expect better yields and longer life especially under intensive cutting cycles.

Lastly, we can take a page from dairy producers. Shortening the cutting interval will improve forage quality and tonnage. The new forage seed is meant for at least three cuts up to five cuts per season.

Ask your AGRIS crop sales specialist to give you a sound fertilizer recommendation based on forage requirements for both quality and tonnage. I would strive to harvest 10, 1000 lb. bales/ season/ acre. I believe this is a reasonable target.

Spring is Coming

Make Sure You Are Signed Up To Get Your Airflow and Spraying Notifications.

It's Not Too Late To Get The Seed You Need

Reach out to your local AGRIS representative to get started, it's not too late 

Download the Ontario Nitrogen Calculator (ONC)



One of the tools we can use to understand the complexity of making a nitrogen recommendation is the Ontario Nitrogen Calculator (ONC).

*Without written express from authors, do not use this information in other publications*

Follow us on our socials for more updates and news!